Have Skein call Threefish, rather than duplicating the code.

3 files changed, 89 insertions, 176 deletions

diff --git a/src/lib/hash/skein/info.txt b/src/lib/hash/skein/info.txt
index 89443132b..82cc69bc2 100644
--- a/src/lib/hash/skein/info.txt
+++ b/src/lib/hash/skein/info.txt
@@ -1,5 +1,5 @@
 define SKEIN_512 20131128
 
 <requires>
-alloc
+threefish
 </requires>
diff --git a/src/lib/hash/skein/skein_512.cpp b/src/lib/hash/skein/skein_512.cpp
index 94c8a3063..38eb3c89f 100644
--- a/src/lib/hash/skein/skein_512.cpp
+++ b/src/lib/hash/skein/skein_512.cpp
@@ -1,6 +1,6 @@
 /*
 * The Skein-512 hash function
-* (C) 2009-2010 Jack Lloyd
+* (C) 2009,2010,2014 Jack Lloyd
 *
 * Distributed under the terms of the Botan license
 */
@@ -9,124 +9,46 @@
 #include <botan/loadstor.h>
 #include <botan/parsing.h>
 #include <botan/exceptn.h>
-#include <botan/rotate.h>
+#include <botan/internal/xor_buf.h>
 #include <algorithm>
 
 namespace Botan {
 
-namespace {
-
-enum type_code {
-   SKEIN_KEY = 0,
-   SKEIN_CONFIG = 4,
-   SKEIN_PERSONALIZATION = 8,
-   SKEIN_PUBLIC_KEY = 12,
-   SKEIN_KEY_IDENTIFIER = 16,
-   SKEIN_NONCE = 20,
-   SKEIN_MSG = 48,
-   SKEIN_OUTPUT = 63
-};
-
-void ubi_512(secure_vector<u64bit>& H,
-             secure_vector<u64bit>& T,
-             const byte msg[], size_t msg_len)
+Skein_512::Skein_512(size_t arg_output_bits,
+                     const std::string& arg_personalization) :
+   personalization(arg_personalization),
+   output_bits(arg_output_bits),
+   m_threefish(new Threefish_512),
+   T(2), buffer(64), buf_pos(0)
    {
-   do
-      {
-      const size_t to_proc = std::min<size_t>(msg_len, 64);
-      T[0] += to_proc;
-
-      u64bit M[8] = { 0 };
+   if(output_bits == 0 || output_bits % 8 != 0 || output_bits > 512)
+      throw Invalid_Argument("Bad output bits size for Skein-512");
 
-      load_le(M, msg, to_proc / 8);
+   initial_block();
+   }
 
-      if(to_proc % 8)
-         {
-         for(size_t j = 0; j != to_proc % 8; ++j)
-           M[to_proc/8] |= static_cast<u64bit>(msg[8*(to_proc/8)+j]) << (8*j);
-         }
+std::string Skein_512::name() const
+   {
+   if(personalization != "")
+      return "Skein-512(" + std::to_string(output_bits) + "," +
+                            personalization + ")";
+   return "Skein-512(" + std::to_string(output_bits) + ")";
+   }
 
-      H[8] = H[0] ^ H[1] ^ H[2] ^ H[3] ^
-             H[4] ^ H[5] ^ H[6] ^ H[7] ^ 0x1BD11BDAA9FC1A22;
-
-      T[2] = T[0] ^ T[1];
-
-      u64bit X0 = M[0] + H[0];
-      u64bit X1 = M[1] + H[1];
-      u64bit X2 = M[2] + H[2];
-      u64bit X3 = M[3] + H[3];
-      u64bit X4 = M[4] + H[4];
-      u64bit X5 = M[5] + H[5] + T[0];
-      u64bit X6 = M[6] + H[6] + T[1];
-      u64bit X7 = M[7] + H[7];
-
-#define THREEFISH_ROUND(X1,X2,X3,X4,X5,X6,X7,X8,ROT1,ROT2,ROT3,ROT4)   \
-      do {                                                             \
-         X1 += X2; X2 = rotate_left(X2, ROT1) ^ X1;     \
-         X3 += X4; X4 = rotate_left(X4, ROT2) ^ X3;     \
-         X5 += X6; X6 = rotate_left(X6, ROT3) ^ X5;     \
-         X7 += X8; X8 = rotate_left(X8, ROT4) ^ X7;     \
-      } while(0);
-
-#define THREEFISH_INJECT_KEY(r)                 \
-      do {                                      \
-         X0 += H[(r  ) % 9];                    \
-         X1 += H[(r+1) % 9];                    \
-         X2 += H[(r+2) % 9];                    \
-         X3 += H[(r+3) % 9];                    \
-         X4 += H[(r+4) % 9];                    \
-         X5 += H[(r+5) % 9] + T[(r  ) % 3];     \
-         X6 += H[(r+6) % 9] + T[(r+1) % 3];     \
-         X7 += H[(r+7) % 9] + (r);              \
-      } while(0);
-
-#define THREEFISH_8_ROUNDS(R1,R2)                         \
-      do {                                                \
-         THREEFISH_ROUND(X0,X1,X2,X3,X4,X5,X6,X7, 46,36,19,37);   \
-         THREEFISH_ROUND(X2,X1,X4,X7,X6,X5,X0,X3, 33,27,14,42);   \
-         THREEFISH_ROUND(X4,X1,X6,X3,X0,X5,X2,X7, 17,49,36,39);   \
-         THREEFISH_ROUND(X6,X1,X0,X7,X2,X5,X4,X3, 44, 9,54,56);   \
-                                                          \
-         THREEFISH_INJECT_KEY(R1);                        \
-                                                          \
-         THREEFISH_ROUND(X0,X1,X2,X3,X4,X5,X6,X7, 39,30,34,24);   \
-         THREEFISH_ROUND(X2,X1,X4,X7,X6,X5,X0,X3, 13,50,10,17);   \
-         THREEFISH_ROUND(X4,X1,X6,X3,X0,X5,X2,X7, 25,29,39,43);   \
-         THREEFISH_ROUND(X6,X1,X0,X7,X2,X5,X4,X3,  8,35,56,22);   \
-                                                          \
-         THREEFISH_INJECT_KEY(R2);                        \
-      } while(0);
-
-      THREEFISH_8_ROUNDS(1,2);
-      THREEFISH_8_ROUNDS(3,4);
-      THREEFISH_8_ROUNDS(5,6);
-      THREEFISH_8_ROUNDS(7,8);
-      THREEFISH_8_ROUNDS(9,10);
-      THREEFISH_8_ROUNDS(11,12);
-      THREEFISH_8_ROUNDS(13,14);
-      THREEFISH_8_ROUNDS(15,16);
-      THREEFISH_8_ROUNDS(17,18);
-
-      // message feed forward
-      H[0] = X0 ^ M[0];
-      H[1] = X1 ^ M[1];
-      H[2] = X2 ^ M[2];
-      H[3] = X3 ^ M[3];
-      H[4] = X4 ^ M[4];
-      H[5] = X5 ^ M[5];
-      H[6] = X6 ^ M[6];
-      H[7] = X7 ^ M[7];
+HashFunction* Skein_512::clone() const
+   {
+   return new Skein_512(output_bits, personalization);
+   }
 
-      // clear first flag if set
-      T[1] &= ~(static_cast<u64bit>(1) << 62);
+void Skein_512::clear()
+   {
+   zeroise(buffer);
+   buf_pos = 0;
 
-      msg_len -= to_proc;
-      msg += to_proc;
-      } while(msg_len);
+   initial_block();
    }
 
-void reset_tweak(secure_vector<u64bit>& T,
-                 type_code type, bool final)
+void Skein_512::reset_tweak(type_code type, bool final)
    {
    T[0] = 0;
 
@@ -135,19 +57,18 @@ void reset_tweak(secure_vector<u64bit>& T,
           (static_cast<u64bit>(final) << 63);
    }
 
-void initial_block(secure_vector<u64bit>& H,
-                   secure_vector<u64bit>& T,
-                   size_t output_bits,
-                   const std::string& personalization)
+void Skein_512::initial_block()
    {
-   zeroise(H);
+   const byte zeros[64] = { 0 };
+
+   m_threefish->set_key(zeros, sizeof(zeros));
 
    // ASCII("SHA3") followed by version (0x0001) code
    byte config_str[32] = { 0x53, 0x48, 0x41, 0x33, 0x01, 0x00, 0 };
    store_le(u32bit(output_bits), config_str + 8);
 
-   reset_tweak(T, SKEIN_CONFIG, true);
-   ubi_512(H, T, config_str, sizeof(config_str));
+   reset_tweak(SKEIN_CONFIG, true);
+   ubi_512(config_str, sizeof(config_str));
 
    if(personalization != "")
       {
@@ -157,50 +78,41 @@ void initial_block(secure_vector<u64bit>& H,
         doesn't seem worth the trouble.
       */
       if(personalization.length() > 64)
-         throw Invalid_Argument("Skein personalization must be <= 64 bytes");
+         throw Invalid_Argument("Skein personalization must be less than 64 bytes");
 
       const byte* bits = reinterpret_cast<const byte*>(personalization.data());
-
-      reset_tweak(T, SKEIN_PERSONALIZATION, true);
-      ubi_512(H, T, bits, personalization.length());
+      reset_tweak(SKEIN_PERSONALIZATION, true);
+      ubi_512(bits, personalization.length());
       }
 
-   reset_tweak(T, SKEIN_MSG, false);
+   reset_tweak(SKEIN_MSG, false);
    }
 
-}
-
-Skein_512::Skein_512(size_t arg_output_bits,
-                     const std::string& arg_personalization) :
-   personalization(arg_personalization),
-   output_bits(arg_output_bits),
-   H(9), T(3), buffer(64), buf_pos(0)
+void Skein_512::ubi_512(const byte msg[], size_t msg_len)
    {
-   if(output_bits == 0 || output_bits % 8 != 0 || output_bits > 64*1024)
-      throw Invalid_Argument("Bad output bits size for Skein-512");
+   secure_vector<u64bit> M(8);
 
-   initial_block(H, T, output_bits, personalization);
-   }
+   do
+      {
+      const size_t to_proc = std::min<size_t>(msg_len, 64);
+      T[0] += to_proc;
 
-std::string Skein_512::name() const
-   {
-   if(personalization != "")
-      return "Skein-512(" + std::to_string(output_bits) + "," +
-                            personalization + ")";
-   return "Skein-512(" + std::to_string(output_bits) + ")";
-   }
+      load_le(&M[0], msg, to_proc / 8);
 
-HashFunction* Skein_512::clone() const
-   {
-   return new Skein_512(output_bits, personalization);
-   }
+      if(to_proc % 8)
+         {
+         for(size_t j = 0; j != to_proc % 8; ++j)
+           M[to_proc/8] |= static_cast<u64bit>(msg[8*(to_proc/8)+j]) << (8*j);
+         }
 
-void Skein_512::clear()
-   {
-   zeroise(buffer);
-   buf_pos = 0;
+      m_threefish->skein_feedfwd(M, T);
+
+      // clear first flag if set
+      T[1] &= ~(static_cast<u64bit>(1) << 62);
 
-   initial_block(H, T, output_bits, personalization);
+      msg_len -= to_proc;
+      msg += to_proc;
+      } while(msg_len);
    }
 
 void Skein_512::add_data(const byte input[], size_t length)
@@ -213,7 +125,7 @@ void Skein_512::add_data(const byte input[], size_t length)
       buffer_insert(buffer, buf_pos, input, length);
       if(buf_pos + length > 64)
          {
-         ubi_512(H, T, &buffer[0], buffer.size());
+         ubi_512(&buffer[0], buffer.size());
 
          input += (64 - buf_pos);
          length -= (64 - buf_pos);
@@ -224,7 +136,7 @@ void Skein_512::add_data(const byte input[], size_t length)
    const size_t full_blocks = (length - 1) / 64;
 
    if(full_blocks)
-      ubi_512(H, T, input, 64*full_blocks);
+      ubi_512(input, 64*full_blocks);
 
    length -= full_blocks * 64;
 
@@ -239,36 +151,20 @@ void Skein_512::final_result(byte out[])
    for(size_t i = buf_pos; i != buffer.size(); ++i)
       buffer[i] = 0;
 
-   ubi_512(H, T, &buffer[0], buf_pos);
-
-   byte counter[8] = { 0 };
-
-   size_t out_bytes = output_bits / 8;
+   ubi_512(&buffer[0], buf_pos);
 
-   secure_vector<u64bit> H_out(9);
+   const byte counter[8] = { 0 };
 
-   while(out_bytes)
-      {
-      const size_t to_proc = std::min<size_t>(out_bytes, 64);
-
-      copy_mem(&H_out[0], &H[0], 8);
-
-      reset_tweak(T, SKEIN_OUTPUT, true);
-      ubi_512(H_out, T, counter, sizeof(counter));
+   reset_tweak(SKEIN_OUTPUT, true);
+   ubi_512(counter, sizeof(counter));
 
-      for(size_t i = 0; i != to_proc; ++i)
-         out[i] = get_byte(7-i%8, H_out[i/8]);
+   const size_t out_bytes = output_bits / 8;
 
-      out_bytes -= to_proc;
-      out += to_proc;
-
-      for(size_t i = 0; i != sizeof(counter); ++i)
-         if(++counter[i])
-            break;
-      }
+   for(size_t i = 0; i != out_bytes; ++i)
+      out[i] = get_byte(7-i%8, m_threefish->m_K[i/8]);
 
    buf_pos = 0;
-   initial_block(H, T, output_bits, personalization);
+   initial_block();
    }
 
 }
diff --git a/src/lib/hash/skein/skein_512.h b/src/lib/hash/skein/skein_512.h
index e0abc06ae..1fd514cf5 100644
--- a/src/lib/hash/skein/skein_512.h
+++ b/src/lib/hash/skein/skein_512.h
@@ -1,6 +1,6 @@
 /*
 * The Skein-512 hash function
-* (C) 2009 Jack Lloyd
+* (C) 2009,2014 Jack Lloyd
 *
 * Distributed under the terms of the Botan license
 */
@@ -8,9 +8,10 @@
 #ifndef BOTAN_SKEIN_512_H__
 #define BOTAN_SKEIN_512_H__
 
-#include <botan/secmem.h>
 #include <botan/hash.h>
+#include <botan/threefish.h>
 #include <string>
+#include <memory>
 
 namespace Botan {
 
@@ -35,13 +36,29 @@ class BOTAN_DLL Skein_512 : public HashFunction
       std::string name() const;
       void clear();
    private:
+      enum type_code {
+         SKEIN_KEY = 0,
+         SKEIN_CONFIG = 4,
+         SKEIN_PERSONALIZATION = 8,
+         SKEIN_PUBLIC_KEY = 12,
+         SKEIN_KEY_IDENTIFIER = 16,
+         SKEIN_NONCE = 20,
+         SKEIN_MSG = 48,
+         SKEIN_OUTPUT = 63
+      };
+
       void add_data(const byte input[], size_t length);
       void final_result(byte out[]);
 
+      void ubi_512(const byte msg[], size_t msg_len);
+
+      void initial_block();
+      void reset_tweak(type_code type, bool final);
+
       std::string personalization;
       size_t output_bits;
 
-      secure_vector<u64bit> H;
+      std::unique_ptr<Threefish_512> m_threefish;
       secure_vector<u64bit> T;
       secure_vector<byte> buffer;
       size_t buf_pos;